You could analyze every possibility here, and gain nothing with it (other than understanding).
A 300smk is both really heavy, and really long. So this variance amounts to microscopic percentages(0.2/300 = 0.07%).
If you ran the numbers in a general sense through QuickLoad, you would not be so concerned about this, over your already existing ES, caused by many other things.
Then there is the possibility that you're not actually isolating bearing, but getting some base angle and/or ogive radius variance affecting your datums of measurement. So then the question is which specifically, by exactly how much, and what are the affects of every combination for real.
The goal is to achieve an Extreme Spread in very low teens or single digits. The lower the better.
Bearing surface variations is commonly suspected as the culprit. Vertical stringing at long distances is proportional to velocity spread.
However, variations in bc are also a factor. Thus included with bearing surface measurement is meplat trimming. There are those here that say it makes a difference beyond 600 yards. I tend to agree with them.
A bit poorer but uniform bc is certainly better than a varying bc from shot to shot.
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
Well, this side of carefully known extremes, AND competent ballistic lab validation, it's all conjecture and folklore.
It could not even be guessed at without painstaking isolation of each specific variance.
For example, a bullet that is heavier 'might' have a lower MV, but a higher BC, combined with a barrel time that releases a bullet on a higher trajectory. Or it may have a higher MV depending on the grove/bore seal and friction, and bullet's extra weight contribution to it's bearing or diameter or length, and/or resulting case fill/powder. This of course completely changes if your bullet's are coated, and might help if the extra .2gr is producing a smaller meplat..
More bearing might mean anything to YOUR bore/groove. It might like the sealing, or hate the friction. The small tension change from extra bearing seated, could put you in & out of an edgy tune.
Every combination of internal and external ballistic affects here could sum to zero, or an extreme, and it's unpredictable without isolation and local validation.
You're soliciting conjecture.
There, I said it...